AMERICAN JOURNAL OF INDUSTRIAL MEDICINE 44:83–93 (2003) The Relationship of Unions to Prevalence and Claim Filing for Work-Related Upper-Extremity Musculoskeletal Disorders Tim Morse, PhD, 5 Laura Punnett, ScD, 1 Nicholas Warren, ScD, MAT , 2 Charles Dillon, MD, PhD, MPH, 3 and Andrew Warren, MPH 4 Background Unionization has been found to be related to higher ﬁling of workers’ com- pensation (WC) claims, but the extent of the relationship and the relationships to other variables have not been previously reported. Methods Telephone interviews were conducted with both a population-based and WC-based samples of musculoskeletal disorder (MSD) cases. Results Workers at unionized facilities were 5.7 times (95% CI 2.5–13.1) more likely to ﬁle a claim for WC, despite a comparable rate of MSD cases. Higher ﬁling was also associated with several measures of MSD severity (1.8–14.1 odds ratios), economic sector (OR ¼ 10.1 for manufacturing), hourly (vs. salary) wages (OR ¼ 2.6), and for having a personal physician (OR ¼ 2.5). Unions appeared to have a protective effect on social effects of work-related MSD. Conclusions Unions appear to improve ﬁling of work-related MSD, particularly for less severe conditions. Thehigher ﬁling doesnot appear to be a case of ‘‘moral hazard,’’ but rather improved and earlier reporting, as is advocated by early intervention approaches to reducing MSD. Am. J. Ind. Med. 44:83 – 93, 2003. ß 2003 Wiley-Liss, Inc. KEY WORDS: musculoskeletal disorders; cumulative trauma disorder; ergonomics; workers’ compensation; unions; claim ﬁling INTRODUCTION Union membership is associated with a higher level of reporting of work-related musculoskeletal disorders (MSD), as well as longer disability periods [Taylor, 1987; Hirsch et al., 1997]. It is not clear, however, what conclusion to draw from these observations and there are several pos- sible explanatory models for such ﬁndings, including ‘‘moral hazard’’ arguments that unions assist workers in ﬁling false or exaggerated claims, that unions assist in ﬁling legitimate claims that would otherwise be unreported, or that the ap- parent relationship is masking a more fundamental associa- tion with higher MSD rates in unionized industries or other co-variates. Unions have a potential impact on health and safety and workers compensation through direct activities, indirect activities, and spurious associations. Direct activities are those that are intended to affect health and safety (primary prevention) or disability following an injury or illness (secondary prevention). Indirect activities are those that are intended to affect other issues, but which also have an im- pact on health and safety. Spurious associations are largely ß 2003 Wiley-Liss, Inc. 1 Department of Work Environment, University of Massachusetts, Lowell, MA 2 ErgoCenter, University of Connecticut Health Center, Farmington, Connecticut 3 National Center for Health Statistics, Division of Health Examination Statistics, CDC Hyattsville, MD 4 Division of Occupational and Environmental Medicine, University of Connecticut Health Center, Farmington, CT 5 Ergonomic Technology Center, University of Connecticut Health Center, Farmington, Connecticut Contract grant sponsor: NIOSH; Contract grant number: RO1CCR112118-03. *Correspondence to: Tim Morse, ErgonomicTechnology Center, University of Connecticut Health Center, Farmington, CT 06030-6210. E-mail: tmorse@nso.uchc.edu Accepted10 March 2003 DOI10.1002/ajim.10234. Published online in Wiley InterScience (www.interscience.wiley.com)